The ultimate goal of this project is to broaden our knowledge of corneal pathophysiology in man through the use of the specular microscope and to develop interpretations of specular microscopy which are clinically useful to the ophthalmologist. Animal and human eyes will be studied, both in vitro and in vivo. Abnormal corneal endothelium will be produced in laboratory animals and the specular microscopic appearance will be correlated with its histopathology. Endothelial healing will be observed in a similar manner. The endothelium of donor corneas will be studied in an attempt to improve the quality of donor tissue for corneal transplantation. The specular microscopic appearance of the endothelium of diseased eyes and the endothelial effects of intraocular surgery will be monitored. Corneal physiology will be studied by comparing the specular microscopic appearance of human endothelium with its permeability as measured with quantitative fluorophotometry in normal and abnormal human eyes.